Potty plans to grow cannabis in the Duchess of Northumberland's dream garden have been put before the Government.

Home Office officials are considering an application from Alnwick Garden for permission to grow cannabis, opium poppies and seeds which can be used to make deadly nerve gas ricin.

The plants are on a list suggested by garden historian, author and award-winning broadcaster Caroline Holmes. She is working as consultant for the Poisons Garden, a planned new feature at the #42m tourist attraction.

She said: "You will not be able to come in and harvest your own cannabis. That was my great, great fear.

"It is meant to be something of a secret place containing wild plants to poison the mind and body."

But access to the walled garden will be strictly controlled with visitors escorted by marshals.

The plants will be grown in cloches designed by the garden's Belgian designer Peter Wirtz to provide climates needed by the plants.

As well as the exotic plants, other poisonous varieties planned for the garden include foxgloves, tobacco plants and wild lettuce, which induces sleep.

Staff at the garden, sensitive to the fact that growing plants that can be used to make drugs is certain to raise eyebrows and cause some criticism, say their intention is to raise awareness about the dangers of drugs, especially in young visitors to the garden.

Ian August, Alnwick Garden liaison officer, has also stressed that the final decision about which plants will go into the Poison Garden has still to be made.

The other themed gardens currently being developed in the second phase of the #42m project are the Labyrinth and the Serpent Garden.

The garden project, which is now being run by a trust, was begun by the Duchess of Northumberland, who dreamed up the plan to transform an old, unused walled garden next to Alnwick Castle.

It is due to be completed by 2008.

Last year it was credited with bringing #13m of visitor spending into Alnwick.

Its first phase included a Grand Cascade, Rose Garden, Ornamental Garden, Woodland Walk and the first car park.

This year's developments will include the world's biggest tree house as well as the three themed gardens.